UNIT 10………STATISTICS section 10.1 and 10.2 scatter plots and linear associations
VOCABULARY:
· Scatter plot: graph to represent 2 types of data
· Association: relationship or connection
· Clustering: grouping together
· Quantitative data: numbers or amounts
· Bivariate data: 2 types of data
· Outlier: a piece of data that doesn’t fit
· Trend: the pattern
· Interpolate: to predict a value IN your data range (very reliable)
· Extrapolate: to predict a value OUTSIDE of your data range ( not as reliable)
TYPES OF ASSOCIATIONS
· STRONG, WEAK OR NONE (if you pick NONE……no other choices below need to be made)
· POSTIVE (goes up) NEGATIVE (goes down)
· LINEAR (makes a line) NON-LINEAR (the pattern does not make a straight line)
LINE OF BEST FIT
· Does not have to start at the origin
· Try to split the data in two…the same amount of data (dots) below the line as above the line)
· Is an approximation
· Uses the line formula: y = mx + b m=slope (rise/run) b=y-intercept
MAKING A GRAPH AND THE LINE OF BEST FIT
· Put a title
· Label the x and y axis with names (what data is each one showing?)
· Use intervals given or figure out intervals that will cover as much of the page as possible
· Put breaks where needed
· Place a dot at each data point….don’t connect
· Draw your line of best fit if it is linear
· Find the slope….pick two points on the LINE (not one of your data points) and find the change in rise……difference up and down….change in y..…and the change in run….difference side to side…change in x. Divide rise/run to find slope…reduce as necessary
· Find the y-intercept….where does your line cross the y-axis?
· Put values in the line formula above
MAKING PREDICTIONS
· Either us the line given to make a prediction (interpolating….using data in range)
· Or……Using the equation of the line that you made……substitute the number you were given in for x and solve for y